1. Field of the Invention
The present invention relates to a self-locking cam for detachably locking a structural member, especially on a motor vehicle seat, and more particularly is concerned with a cam assembly including a stationary pivot axle, a cam body supported on the pivot axle, and a biased locking latch and roller associated with the cam body and pivot axle such that a locking surface of the cam body, when the locking latch and roller are in a locked position, is retained in contact with the structural member so as to hold the cam assembly in a self-locking state.
2. Description of the Prior Art
A cam of a self-locking type is known for example from German patent document No. DE 44 17 491 A1. This document describes a capture hook with a configuration adapted for a foldable backrest foldably articulated on the seat part of a motor vehicle seat. The capture hook with this configuration is intended to prevent the backrest from unintentionally folding forward during strong negative acceleration such as occurs for example in the event of a crash. The self-locking cam is provided for securement of the capture hook in a locking position. When the capture hook is in the locking position, this cam has a rising locking surface in contact on a pressure surface of the capture hook such that the cam is self-locking.
The self-locking cam is connected with a detachment member, for example a Bowden cable, with the aid of which the cam can be pivoted about the pivot axis should the backrest be folded forward. The actuation forces for detaching the cam from the pressure surface of the capture hook depend on the strength of the self-locking developed between the locking surface of the cam and the pressure surface of the capture hook. Maximum self-locking strength is desirable in order to have large holding forces for the capture hook to be secured. This applies to all structural members to be secured or locked with a cam of the self-locking type. However, it is therein true that the greater the holding forces produced from the self-locking the greater the actuation forces required for detaching the cam. According to the prior art, for example also in the construction disclosed in the above-cited German patent document No. DE 44 17 491 A1, as a compromise the self-locking strength is therefore selected in which the actuation forces for detaching the cam can be supplied without any problems by persons of normal physical strength.